Friction drives have been known in many different applications for many years. In particular, it has often been proposed to provide a friction drive, using an internal combustion engine as the power source, for driving the front or rear wheel of a lightweight vehicle such as a bicycle. While these devices are well known, they have not always been constructed with both convenience and safety of operation in mind.
The principle objects of this invention are therefore to provide an apparatus for frictionally driving a light weight vehicle which is safe, reliable, and low cost, which is convenient to operate, which has a convenient means for engaging the drive with and releasing the drive from contact with the vehicle wheel, and which provides an interlock safety system to insure the safety of the vehicle and its operator, for example, while the engine fuel tank is being refilled.